Journal of Volcanology and Geothermal Research最新文献

{"title":"Intense explosive activity in the early Holocene at Pico de Orizaba volcano: Revisiting the Xilomich eruptive episode","authors":"Delphine Sourisseau ,&nbsp;José Luis Arce ,&nbsp;José Luis Macías ,&nbsp;Laura E. Beramendi-Orosco ,&nbsp;José Juan Carrillo-Mondragón ,&nbsp;Galia González-Hernández","doi":"10.1016/j.jvolgeores.2025.108433","DOIUrl":"10.1016/j.jvolgeores.2025.108433","url":null,"abstract":"<div><div>Pico de Orizaba is a Pleistocene to Holocene stratovolcano located in the easternmost part of the Trans-Mexican Volcanic Belt. Repeated cycles of dome growth and collapse, along with Vulcanian to Plinian explosive activity, have occurred during the past 650 ka. These eruptions have produced a complex sequence of scoria-and-ash, pumice-and-ash, block-and-ash flows and pumice fallout, interbedded with andesitic to dacitic lava flows that constitute the modern volcanic edifice (Citlaltépetl volcano). Based on detailed field descriptions, stratigraphic correlations, grain size and componentry analyses, and five new ¹⁴C radiocarbon ages, we reconstruct the eruptive history of the Xilomich eruptive episode deposited south of Pico de Orizaba. Our results indicate that at least ten pyroclastic flows were emplaced during the Xilomich eruptive episode between 8980 and 8170 years BP. These deposits record the occurrence of at least four Vulcanian eruptions and two dome-destruction events, which generated scoria-and-ash and block-and-ash pyroclastic flows. Pyroclastic flows generated by eruptions comparable to the Xilomich episode could extend as far as populated areas like Maltrata, Ciudad Mendoza, and Orizaba, located within a 30-km radius, posing a potential threat to approximately 310,500 inhabitants south of Pico de Orizaba.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108433"},"PeriodicalIF":2.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magma ascent dynamics and transport process of the Mt. Semeru lava dome that collapsed on 4th December 2021 (East Java, Indonesia)","authors":"Indranova Suhendro ,&nbsp;Muhammad Andriansyah Gurusinga ,&nbsp;Atsushi Toramaru ,&nbsp;Agung Harijoko ,&nbsp;Haryo Edi Wibowo ,&nbsp;Gammanda Adhny El-Zamzamy Latief ,&nbsp;Pandu Eka Priyana ,&nbsp;Muhammad Alsamtu Tita Sabila Pratama Suhartono ,&nbsp;Zulfa Yogi Rahmawati","doi":"10.1016/j.jvolgeores.2025.108432","DOIUrl":"10.1016/j.jvolgeores.2025.108432","url":null,"abstract":"<div><div>This study aimed to discuss the magma ascent dynamics and transport process of the Mt. Semeru lava dome that collapsed on 4th December 2021 by coupling the field data with analysis of crystal textures (phenocrysts and microlites) and whole-rock geochemistry of clasts embedded in the 2021 pyroclastic density currents (PDCs) of the channel facies. We identify four clast types within the channel PDC facies, namely vesicular-black and porphyritic (V-BP), dense-grey and porphyritic (D-GP), dense-grey and highly porphyritic (D-GhP), and vesicular-reddish and weakly porphyritic (V-RwP). The V-BP, D-GP, and D-GhP clasts are free of olivine, having identical phenocryst size distribution (avg. slope − 3.0) and whole-rock composition of high Zr/Y basaltic andesites (∼56.5 wt% SiO₂; Magma A). Meanwhile, the V-RwP clast includes some olivine, has a characteristically steeper slope of the phenocryst crystal size distribution (CSD) (−3.8), and is classified as low Zr/Y basalt (∼51 wt% SiO₂; Magma B). This evidence suggests the occurrence of at least two magma reservoirs beneath Semeru. Judging from Semeru's historical record, dome formation via the extrusion of Magma A took place between 2004 and 2012, while Magma B was extruded before dome formation (between 1941 and 1994) and produced lava flows and V-RwP clasts; the latter was carried by the 2021 PDCs and thus classified as accidental lithics. The V-BP yielded the steepest CSD slope of plagioclase microlites (−50.8), followed by D-GP (−43.7) and D-GhP (−24.3), suggesting that the type A magma ascended and quenched at different rates. The less porphyritic and more gaseous magma quickly reaches the surface, resulting in V-BP with relatively small microlite size and steeper CSD. While the more porphyritic and gas-poor magma ascends slowly, resulting in slower cooling and thus facilitating the microlites to attain a larger size with gentler microlite CSD. The increasing SO₂ emissions and the presence of harmonic tremors before the collapse event suggest that the dome was destabilized by the ascending magma, forming initially hot PDCs. However, heavy rainfalls (∼15 mm/h) successfully turned the PDCs into wet and cold (&lt;100 °C) conditions, as evidenced by the prevalence of accretionary lapilli in the overbank facies and unsinged trees and wooden and plastic materials.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108432"},"PeriodicalIF":2.3,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exposing electrical conductivity anomalies beneath Mount Erciyes, Cappadocia, Türkiye","authors":"Sabri Bülent Tank,&nbsp;Serkan Üner ,&nbsp;Ruken Yazıcı,&nbsp;Mustafa Karaş","doi":"10.1016/j.jvolgeores.2025.108428","DOIUrl":"10.1016/j.jvolgeores.2025.108428","url":null,"abstract":"<div><div>Three-dimensional electrical conductivity models for Mount Erciyes, the most prominent stratovolcano at the Cappadocia Volcanic Province in Central Anatolia, Türkiye, were developed from magnetotellurics (MT) data collected at thirty-eight sounding locations. Analyses including electromagnetic impedance tensor and phase tensor calculations were employed to portray the conductivity variations, to reveal the dimensionality of the dataset and to detect the principal geo-electric strike direction in the area. Next, several trial models were developed including and excluding topography information as well as different starting models and other modeling parameters. Results achieved from all of the inverse calculations and particularly the final model suggested that (i) high electrical conductivity (&lt;10 Ωm) values are obtained for multiple anomalies distributed beneath the complex reaching to depths of around 4–6 km from the summit, (ii) these anomalies coincide with the parasitic cones and the vents associated with the Mount Erciyes, (iii) the northeast-southwest trending faults that bound the Erciyes Basin and the wrench zone that cut across the main volcano complex act as barriers for the fluid flow.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108428"},"PeriodicalIF":2.3,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kronotsky Volcano – A low-K end-member frontal volcano in Kamchatka: Geological structure and composition of rocks and minerals","authors":"Natalia Gorbach ,&nbsp;Daria Tobelko ,&nbsp;Georgy Ovsyannikov ,&nbsp;Alexey Rogozin ,&nbsp;Vasiliy Shcherbakov ,&nbsp;Anastasia Plechova ,&nbsp;Maxim Portnyagin","doi":"10.1016/j.jvolgeores.2025.108430","DOIUrl":"10.1016/j.jvolgeores.2025.108430","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Kronotsky volcano is the largest but poorly studied stratovolcano in the frontal zone of the Kamchatka arc. Here we present the first systematic data on the geological structure of this volcano and the composition of its rocks and minerals. Kronotsky lavas are predominantly low-K, high-Fe tholeiitic basalts to basaltic andesites with SiO&lt;sub&gt;2&lt;/sub&gt; = 47.0–53.2 wt%, K&lt;sub&gt;2&lt;/sub&gt;O = 0.24–0.65 wt%, FeO&lt;sup&gt;⁎&lt;/sup&gt; = 9.1–13.4 wt% and MgO = 3.7–11.2 wt%. Andesites (SiO&lt;sub&gt;2&lt;/sub&gt; = 59.9–60.5 wt%, K&lt;sub&gt;2&lt;/sub&gt;O = 0.65 wt%, FeO&lt;sup&gt;⁎&lt;/sup&gt; = 7.7–7.6 wt%, MgO = 2.4–2.6 wt%) are rare and occur among the lava cones and necks from the latest stage of activity. The major phenocrysts in Kronotsky basalts are olivine (Fo&lt;sub&gt;91.9&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;67&lt;/sub&gt;), plagioclase (An&lt;sub&gt;95&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;40&lt;/sub&gt;) and high-Ca pyroxene (Mg#&lt;sub&gt;89.3&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;50&lt;/sub&gt;). Orthopyroxene occurs as phenocrysts (Mg#&lt;sub&gt;61&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;67&lt;/sub&gt;) in the andesites and rarely in the basaltic andesites, and as inclusions (Mg#&lt;sub&gt;83&lt;/sub&gt;) in the high Ca-pyroxene glomerocrysts of the most mafic varieties of basalts. Ti-magnetite (Fe&lt;sup&gt;2+&lt;/sup&gt;/Fe&lt;sup&gt;3+&lt;/sup&gt; = 0.98–1.51, TiO&lt;sub&gt;2&lt;/sub&gt; = 11.0–16.5 wt%) forms subphenocrysts in andesites and microlites in the groundmass of basalts. Inclusions of Cr-spinel (Cr/Cr + Al = 0.19–0.79, TiO&lt;sub&gt;2&lt;/sub&gt; = 0.18–2.81 wt% and Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; = 8.7–33.2 wt%) are found in olivine phenocrysts. Variations of whole rock and mineral compositions reflect the existence of long-lived magma chamber(s) under the volcano and the processes of crystal differentiation, accumulation and magma mixing as well as crystallization associated with magma degassing during ascent and decompression.&lt;/div&gt;&lt;div&gt;Compared to all Quaternary volcanoes on Kamchatka, Kronotsky basalts are the most depleted in K&lt;sub&gt;2&lt;/sub&gt;O (down to 0.24 wt%) and a number of other incompatible elements (Ti, Zr, Nb, LREE), and are characterized by the lowest Nb/Zr (≤0.02) and Nb/Yb (≤0.5) ratios. In contrast, Ba/Nb (up to 280) and especially Ba/Th (up to 938) ratios are relatively high compared to other Kamchatka volcanoes. The composition of high-Mg olivine (Fo ≥ 87.5 mol%, Ni ≤2500 ppm, Fe/Mn = 56–71) indicates that the primary magmas of Kronotsky volcano originated from a peridotite mantle source. Trace element modeling suggests that the mantle was melted to a high degree (up to 25 %) and was more depleted than the source of typical MORB and of most parental magmas in Kamchatka. The exceptionally high degree of melting, combined with a strong relative enrichment in fluid mobile elements, suggests an enhanced fluid flux from the subducting Pacific plate beneath Kronotsky volcano, which is responsible for the extensive mantle melting. The Krusenstern fracture zone on the Pacific plate, subducting beneath central Kamchatka, may supply abundant hydrous fluids to the mantle wedge beneath Kronotsky volcano, contributing to its distinct","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108430"},"PeriodicalIF":2.3,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What Triggered the 2021 eruption at Nyiragongo volcano (D.R. Congo)? Unraveling the Complex Interplay between tectonism and magmatism","authors":"Thystere Matondo Bantidi ,&nbsp;Takeshi Nishimura ,&nbsp;Kazuyoshi Nanjo ,&nbsp;Bogdan Enescu ,&nbsp;Takeo Ishibe ,&nbsp;Georges Mavonga Tuluka","doi":"10.1016/j.jvolgeores.2025.108429","DOIUrl":"10.1016/j.jvolgeores.2025.108429","url":null,"abstract":"<div><div>After a 20-year repose, Nyiragongo volcano in the eastern Democratic Republic of the Congo experienced a flank eruption on May 22, 2021, claiming over 30 lives and causing substantial economic loss. Despite extensive studies, the eruption's triggering mechanism remains unclear. In this study, we analyze earthquakes beneath the volcano's summit to examine the <em>b</em>-value variations in the Gutenberg–Richter law, which reflects the ratio of small to large earthquakes and inversely correlates with differential stress. Our goal is to track magma system dynamics leading to the eruption and identify its catalyst. We observe notable differences in <em>b</em>-value estimates during the pre- and <em>syn</em>-eruptive phases. First, the <em>b</em>-value consistently increases over 20 % above the background level (<span><math><msub><mi>b</mi><mi>ref</mi></msub></math></span> = 0.94) for a few days, peaking at 1.55 two days before the eruption, then drops to 59 % below the <span><math><msub><mi>b</mi><mi>ref</mi></msub></math></span> during the eruption. In the six hours following the eruption, <em>b</em>-values fluctuate around 90 % of the <span><math><msub><mi>b</mi><mi>ref</mi></msub></math></span>. These elevated <em>b</em>-values likely reflect the activation of small cracks from the influx of magma in the vicinity of the volcano. Additionally, Coulomb stress changes calculated by combining the epidemic-type aftershock sequence (ETAS) model with the rate-and-state model reveal a stress increase of approximately 10.5 MPa just before the eruption. To address the issue of missing events caused by seismic network density incompleteness and short-term aftershock incompleteness, we created a replenished catalog. Analyzing this catalog, we successfully reproduced <em>b</em>-values, demonstrating its reliability for analyzing volcanic seismicity in regions with sparse networks. Our findings underscore the importance of incorporating systematic <em>b</em>-value time series analysis into regular volcano monitoring programs to improve forecasting capability.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108429"},"PeriodicalIF":2.3,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracing the pre- to post-eruptive crystallization of trachybasaltic melts: insights into the 1651–1654 CE lavas of Mount Etna (Sicily, Italy)","authors":"G. Lanzafame ,&nbsp;S. Peres ,&nbsp;F. Casetta ,&nbsp;R. Abart ,&nbsp;M. Prašek ,&nbsp;S. Portale ,&nbsp;P.P. Giacomoni ,&nbsp;E. Libowitzky ,&nbsp;C. Ferlito","doi":"10.1016/j.jvolgeores.2025.108416","DOIUrl":"10.1016/j.jvolgeores.2025.108416","url":null,"abstract":"<div><div>Understanding the crystallization of silicate melts is key to reconstructing the processes occurring from magma rising to lava emplacement, the latter representing a major hazard for human settlements during effusive eruptions. Crystal growth, along with melt H₂O degassing, strongly influences lava rheology and surface flow behaviour. This study investigates the pre- to post-eruptive crystallization dynamics of trachybasaltic melts from the 1651–1654 CE eruption on Mount Etna's western flank (Sicily, Italy), one of the 17th century's most significant events due to its duration, lava field extent, and reach into inhabited areas. Investigation on different layers of a fractured pressure ridge allowed to reconstruct the crystallization history of a single flow unit, revealing significant textural differences between the inner and outer (crust) portion of the lava, allowing to quantify the extent of crystallization at subaerial conditions. By combining 2D and 3D textural analyses with chemical and mineralogical investigations, the pre-eruptive pressure-temperature (P–T) conditions of crystal formation were constrained. Phenocrysts nucleated in a vertically extended feeding system (down to 23 km below the sea level) at almost stationary condition of <em>T</em> = 1070–1060 °C. In the glass-rich crust, detailed chemical and textural analyses revealed chemical boundary layers around plagioclase microlites, which was used to model a subaerial growth rate of the outermost plagioclase rim in the order of 0.2–4.5 μm/s. These findings enhance our understanding of lava behaviour during flow, offering key insights for improving hazard models, monitoring, and response during effusive volcanic events similar to the 1651–1654 CE eruption.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108416"},"PeriodicalIF":2.3,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Degassing, porosity and hydration age characteristics of a giant submarine lava dome: Implications for post-caldera volcanism of the Kikai caldera, Japan","authors":"Iona M. McIntosh ,&nbsp;Morihisa Hamada ,&nbsp;Takeshi Hanyu ,&nbsp;Reina Nakaoka ,&nbsp;Maria Luisa G. Tejada ,&nbsp;Takashi Miyazaki ,&nbsp;Kenta Ueki ,&nbsp;Bogdan S. Vaglarov ,&nbsp;Tomoki Sato ,&nbsp;Satoru Tanaka ,&nbsp;Katsuya Kaneko ,&nbsp;Koji Kiyosugi ,&nbsp;Yojiro Yamamoto ,&nbsp;Keiko Suzuki-Kamata ,&nbsp;Nobukazu Seama ,&nbsp;Yoshiyuki Tatsumi","doi":"10.1016/j.jvolgeores.2025.108427","DOIUrl":"10.1016/j.jvolgeores.2025.108427","url":null,"abstract":"<div><div>The mostly submarine Kikai caldera in SW Japan underwent a caldera-forming eruption at 7.3 ka. Its subsequent post-caldera volcanic activity has included subaerial eruptions whose onland deposits have been well studied, and a historical island-forming eruption from a submarine vent. Marine surveys have also documented a giant, 32 km³ submarine dome that has been emplaced on the caldera floor during the post-caldera period, but the timing and style of its eruption is not known. Here we investigate this giant submarine dome using seafloor observations and rock samples collected during dredging surveys. The dome is covered by large blocks; based on porosity, matrix glass volatile contents and thermal demagnetisation data we infer that these are giant pumice that floated hot at the sea surface prior to sinking. Without suitable radiocarbon material we instead use the extent of secondary hydration of giant pumice matrix glasses to estimate eruption age, yielding an age of 13th Century CE or younger. We infer that the dome grew both endogenously under a thin sediment covering and also via exogenous seafloor lava flow, and that the giant pumice formed from a pumiceous carapace on this lava. We also find preliminary textural evidence that this shallow submarine dome was formed by cryptic fragmentation and pyroclast sintering as is proposed for subaerial silicic lavas. Together our findings suggest that the Kikai caldera has a high average eruption rate in its current post-caldera volcanic stage, and that eruptions, potentially explosive, from submarine vents comprise a significant portion of this activity.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108427"},"PeriodicalIF":2.3,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pre-eruptive conditions of Mid-to-Late Holocene eruptions from Lonquimay Volcanic Complex, Southern Andes of Chile","authors":"Matías Poblete ,&nbsp;Angelo Castruccio ,&nbsp;Patricia Larrea ,&nbsp;Francisco Cáceres ,&nbsp;Jorge Romero ,&nbsp;Oscar Bustamante","doi":"10.1016/j.jvolgeores.2025.108425","DOIUrl":"10.1016/j.jvolgeores.2025.108425","url":null,"abstract":"<div><div>Lonquimay Volcanic Complex (38°22′S, LVC) is one of the most active volcanoes in the Southern Volcanic Zone of the Andes. It comprises a main composite volcano and twelve monogenetic cones, and it has erupted since the Upper Pleistocene. Its latest eruption was in 1988–90 and had catastrophic consequences for the human health and environment. Here we estimated and compared key pre-eruptive conditions (pressure, temperature, dissolved H₂O content and crystallinity) from three of the most well-exposed and widespread fall deposits from the composite volcano, and three lavas of the volcanic complex. Magmas that fed the analysed eruptions were basaltic to trachytic in composition and contained a mineral assemblage of plagioclase±olivine±clinopyroxene and minor Fe<img>Ti oxides and apatite. Evolved units contain unique fayalitic autocrysts (as low as Fo₂₁), which are proposed to have formed in a magma (1) under low pressure, (2) with an evolved composition, (3) a high Fe content, and (4) a reducing state. Based on geochemistry and thermobarometric calculations, we suggest two magma storage zones: (1) a deeper hot and mafic storage region (∼12 km) that host basaltic to basaltic-andesitic magmas at 1083–1151 °C, which undergo tholeiitic mafic injections and (2) a cooler and evolved eruption-feeding magmatic system with a major storage region at 5.6 km with magmas at 869–1046 °C, where fractional crystallisation, magma injections, mingling, and convection took place. Although the same magma injection and mingling triggering-mechanism is suggested for explosive and effusive eruptions, we suggest mingling timescale plays a key role in controlling eruptive style, along with volatile composition and microcryst content.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108425"},"PeriodicalIF":2.3,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultraviolet and visible remote sensing of volcanic gas emissions","authors":"Christoph Kern","doi":"10.1016/j.jvolgeores.2025.108423","DOIUrl":"10.1016/j.jvolgeores.2025.108423","url":null,"abstract":"<div><div>As magma rises in volcanic systems, volatile species exsolve from the silicate melt and are emitted as gases into the atmosphere. Measuring the magnitude and composition of gas emissions from volcanoes provides insights into processes occurring deep within the Earth and helps constrain the impact of volcanic degassing on atmospheric chemistry. Optical remote sensing techniques allow volcanic gas emissions to be characterized without the need to access hazardous areas near active volcanic vents. This paper reviews the state of the art in ultraviolet and visible volcanic gas remote sensing from the ground, air, and space. Special attention is given to discussing the physics of atmospheric radiative transfer on which these techniques are based. The functionality and limitations of different remote sensing instruments are examined, making clear that the ideal choice of instrumentation will depend on the volcanic system to which it is applied and the sought measurement parameters. Common algorithms for determining trace gas column densities, gas burdens, and volcanic emission rates from measurements of spectral radiance are outlined and compared, showing how some algorithms attempt to model the physics of the measurement while others maximize sensitivity. Several examples demonstrate how remote sensing measurements continue to advance our understanding of volcanic systems and their impact on the atmosphere. Finally, a few promising directions of inquiry are suggested that could lead to improvements in remote sensing instrumentation and analysis techniques. By combining spectroscopic and imaging techniques, improving our understanding of atmospheric radiative transfer, expanding the suite of target gases, and increasing the coverage and frequency of observations, we stand to significantly improve our ability to detect and quantify volcanic gas emissions and gain new insights into important Earth-system processes.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108423"},"PeriodicalIF":2.3,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magmatic evolution and timescales of the Naruko caldera system (NE Honshu): Insight from orthopyroxene and quartz mineral zoning","authors":"Alexey Kotov ,&nbsp;Noriyoshi Tsuchiya ,&nbsp;Satoshi Okumura ,&nbsp;Masao Ban ,&nbsp;Masaoki Uno ,&nbsp;Isoji Miyagi ,&nbsp;Kenji Shimizu ,&nbsp;Takayuki Ushikubo ,&nbsp;Geri Agroli ,&nbsp;Shumpei Yoshimura ,&nbsp;Manzshir Bayarbold","doi":"10.1016/j.jvolgeores.2025.108415","DOIUrl":"10.1016/j.jvolgeores.2025.108415","url":null,"abstract":"<div><div>Silicic magmas from large caldera-forming eruptions often represent crystal-poor melts separated from highly crystalline mush zones under the influence of heat and volatiles. The cascade of magmatic processes from the formation of partially molten crustal zones to the extraction of magma from mush and its interaction with hotter intrusions creates intricate chemical zoning and textures in phenocrysts, reflecting diverse magmatic processes. Understanding the mechanisms and timescales of eruptible magma extraction and storage remains a fundamental challenge in the volcanology. To address this, we present diffusion chronometry from Fe<img>Mg in orthopyroxenes and Ti in quartz from two Pleistocene caldera-forming eruptions at Naruko Caldera, Japan with the Nizaka (73 ka, ∼2.5 km³) and Yanagisawa (45 ka, ∼10 km³) Tuffs. Our findings suggest that both eruptions tapped a broadly similar crustal storage zone, but differences in extraction and localization prior to the eruption influenced the mineral assemblages (e.g., amphibole presence in Yanagisawa but not in Nizaka). Olivine and high-Mg pyroxenes, along with widespread reverse zoning, indicate significant mafic recharge during magma extraction and immediately before eruption. We propose that the Nizaka magma was physically separated from the mush, stored under cooler and less oxidized conditions, and experienced less intrusion by hot magmas, whereas the Yanagisawa magma remained in situ, forming a hotter reservoir that preserved amphibole stability. Despite these differences, the Fe<img>Mg interdiffusion in orthopyroxenes suggests that both magmas were generated within ∼300 years, with peak accumulation rates occurring within ∼30 years of eruption. Ti diffusion in quartz has a shorter timescale (&lt;30 years), capturing only the final stages of crystallization. Our results support the notion that eruptible silicic magmas might be assembled over short timescales prior to eruption regardless of their volume, which is consistent with the results of previous studies.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108415"},"PeriodicalIF":2.3,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}